borderland vs horizon

borderland

noun
  • Land near a border; marches. 

horizon

noun
  • The visible horizontal line (in all directions) where the sky appears to meet the earth in the distance. 

  • A specific layer of soil, or stratum 

  • The point at which a computer chess algorithm stops searching for further moves. 

  • Any level line or surface. 

  • The range or limit of one's knowledge, experience or interest; a boundary or threshold. 

  • A cultural sub-period or level within a more encompassing time period. 

  • The range or limit of any dimension in which one exists. 

How often have the words borderland and horizon occurred in a corpus of books? (source: Google Ngram Viewer )